US6239555B1ExpiredUtility

Flashlight

Priority: Apr 6, 1999Filed: Sep 8, 2000Granted: May 29, 2001
Est. expiryApr 6, 2019(expired)· nominal 20-yr term from priority
F21L 4/005F21L 13/06H05B 39/09F21Y 2115/10Y02B20/30H05B 45/395
89
PatentIndex Score
54
Cited by
24
References
2
Claims

Abstract

A flashlight includes a source of power, a source of light, and switching circuitry connected with the source of power and the source of light. The source of light is a semiconductor diode capable of emitting white light when energized. The source of power may be a battery or a generator. The switching circuitry is operable between an on condition and an off condition. When the switching circuitry is in the off condition, it is effective to energize the semiconductor diode to provide light of a low intensity to facilitate locating the flashlight. When the switching circuitry is in the on condition, it is effective to energize the semiconductor diode to emit white light of an intensity sufficient to illuminate objects spaced more than six feet from the flashlight. The switching circuitry includes a transistor which is operated between conducting and non-conducting conditions by a flip/flop in response to manual actuation of a pushbutton.

Claims

exact text as granted — not AI-modified
Having described the invention, the following is claimed:  
     
       1. A flashlight comprising a source of power, a diode capable of emitting white light when energized, and electrical circuitry connected with said source of power and said diode, said electrical circuitry including a field effect transistor which is operable between a plurality of conditions, said field effect transistor being operable between a first condition in which said electrical circuitry is effective to energize said diode with a first electrical potential to cause said diode to emit white light of a first intensity, a second condition in which said electrical circuitry is effective to energize said diode with a second electrical potential which is less than said first electrical potential to cause said diode to emit white light of a second intensity which is less than said first intensity, and a third condition in which said electrical circuitry is ineffective to energize said diode and said diode is ineffective to emit light, said diode being energized to emit white light of an intensity sufficient to illuminate objects spaced more than six feet from said flashlight when said field effect transistor is in the first condition, said diode being energized to emit white light of an intensity which is insufficient to illuminate objects spaced more than six feet from said flashlight when said field effect transistor is in the second condition. 
     
     
       2. A flashlight set forth in claim  1  further including regulator means for maintaining the intensity of the white light emitted from said diode substantially constant when said field effect transistor is in the first condition with a decrease in the strength of said source of power.

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